Managing bronze beetle <i>Eucolaspis brunnea</i> in organic apple orchards

Abstract

Bronze beetle (Eucolaspsis brunnea) is threatening the viability of New Zealands organic apple industry This study investigated the efficacy of organic insecticides against bronze beetle trialled adult emergence traps measured fruit damage caused by adult feeding and sampled larvae in the soil Laboratory bioassays of ten organically acceptable insecticides failed to identify an effective product to control adult bronze beetle Emergence trapping on two orchards showed that bronze beetle emergence peaked during November Bronze beetle damage on cv Royal Gala apples was highly variable among the 12 orchards surveyed and ranged from 2 to 43 immediately before harvest Royal Gala apples had much more damage when inspected in field bins than cv Braeburn apples Soil sampling suggested that most bronze beetle larvae are found 51150 mm below the soil surface during autumn